Former Sri Lanka test skipper Dimuth Karunaratne will retire from the format after his 100th match, the final test of Sri Lanka's two-test series against Australia in Galle on Thursday.

Former Sri Lanka captain Dimuth Karunaratne will retire from international cricket after playing his 100th Test. Sri Lanka are scheduled to take on Australia in the second and final Test in Galle from 6 February.

Australia captain Steve Smith backed number three batter Marnus Labuschagne to regain his form and hinted spin-bowling all-rounder Cooper Connolly could make his test debut in the second match against Sri Lanka on Thursday.

The rainy weather conditions have given Australia a selection problem for the opening test against Sri Lanka starting Wednesday, although one thing seems certain: Travis Head will open the batting.

Dimuth Karunaratne is set to become only the seventh Sri Lanka player to feature in 100 Tests. His landmark game will be his last in international cricket, bringing down curtains on a near-14-year career for Sri Lanka.

Sri Lanka opener Dimuth Karunaratne will retire from Test cricket after this week's second Test - and his 100th - against Australia in Galle.